Control means for centrifugal pumps



May 31,1932 F. B. ALLEN CONTROL MEANS FOR CENTRIFUGAL PUMPS Filed May 31, 1929 A ORNEY5 PPAA/A.B.All-FA/ BY Patented May 31, 1932 UNITED STATES PATENT oFFicE FRANK n. ALLEm or rowan. MERION 'rownsm, momeomnmr COUNTY, PENNSYL- VANIA, ASSIGNOR 'ro 'IHE-ALLEN-SHERMAN-HOFF comm, A CORPORATION or PENNSYLVANIA CONTROL MEANS FOR CEN'IBIFUGAL PUMPS Application filed May 31,

tive chambers so that non-injurious fluid will flow from one chamber into another chamber 15 through which liquid containing injurious material is passing. This proposal is dependent for complete success on the provision of an adequate supply of liquid substantially free from injurious material to the chamber in which the higher pressure is created; and where this supply is subject to failure the foregoing proposed construction may not prevent ingress of liquid carrying injurious substances to the 25 parts of the pump from which it is desired that they be excluded.

Accordingly by the present invention I have provided means for automatically deenergizing the pump driving means, which de-energizing means operates when the pressure differential between the communicating chambers falls below a predetermined amount.

In the drawing accompanying and forming a part of this specification the figure is a side elevational view, partly diagrammatic and partly in section showing one form of app paratus embodying my invention.

In the drawing 1 designates a base of any suitable construction upon which is mounted an electric motor 2, a shaft support 3 and a pump casing 4. A shaft attached to the motor 2 extends through suitable bearings 6 carried by the member 3 and projects into the casing, 4 of a centrifugal pump. The shaft 5 carries within the casing 4 an impeller 7 provided with a hub portion 8 attached to the shaft 5, a disc 9 preferably inte- 50 gral with the hub 8 and impeller blades 10 isposed on one side of the disc 9. A disc 11 1929. senfin n. 887,588.

serves as a cover for blades 10 and its outer surface is disposed closely adjacent to the lateral side wall12 of the casing 4. The disc 9 also carries auxiliary blades 13 preferably integral therewith and disposed on the side thereof opposite to the blades 10. The disc 9 at its periphery forms with thetadjacent portion of the casing an annular passage between the chamber 14 in which the auxiliary blades 13 are disposed and the main chamber 15 in which the main blades 10 are disposed.

The side wall 16 or engine side plate of the casing 4 is provided with a stufiing box 17 through which the shaft 5 extends and in which packing material 18 is disposed and held in position by a packing gland 19. The wall 16 forms a chamber 20 about the shaft and its bearing 21, which chamber communicates with the chamber 14 and has a conduit 22 leading thereinto for supplying liquids substantially free from injurious materials to the chambers 20 and 14.

The side plate 12, is provided with the suction inlet opening 23 for entry of liquids containing injurious materials to the chamber 15 and casing 4, the chamber 15 having a suitable outlet or discharge opening (not shown) Conduits 24 and 25 communicate respectively with chambers 15 and 14 and with suitable means for de-energizing motor 2. The means shown for de-energizing the motor consists of a valve 26 having a diaphragm 27 therein which divides the interior of the valve 26 into a chamber 28 which is in communication with conduit 24 and a chamber 29 in communication with conduit 25. A spring 30 in chamber 28 surrounds a rod 31 and is compressed between the diaphragm 27 and one Wall of the valve 26'. The rod 31 projects through the valve and is pivotally connected to an arm 32 which constitutes a part of the electrical circuit through which current may flow to the motor 2. This circuit includes lines 33 and 34 and a cutout switch 35.

The operation of the above described embodiment of my invention is as follows:

In starting the pump liquids substantially free from injurious substances are admitted under pressure through conduit 22 into chambers 20 and 14. When the pressure difierential between chambers 14 and 15 reaches the redetermined amount the diaphragm 27 will be moved to compress spring 30 and move arm 31 to complete the electrical circuit from the switch 35 which has previously been closed through the lines 33 and 34 to the motor, whereupon the motor 2 will be energ zed and the impeller 7'will be rotated. I

The auxiliary blades 13 will mainta n the pressure difi'erential above the predetermined minimum so long as the supply of liquid through conduit 22 continues in a suilicxent amount, but when that supply is dimmished below a certain amount or cut off completely the pressure in chamber 14 will drop and 1f the drop is sufficient the spring 30 Wlll move the diaphragm 27 and pull rod 31 toward the valve 26 with resultant interruption of the electrical circuit due to the opening switch of which arm 32 is a part. The pump will then stopbefore a suflicient amount of liquid containing injurious material has penetrated into the chamber 14 and bearing 21 to injure the bearing.

Having thus described my invention so that those skilled in the art may be enabled to practice thesame, what I desire to secure by Letters Patentisdefined in what is claimed.

What is claimed is:

1. The combination with a centrifugal pump having a I plurality of communicating chambers, means for driving the; pump and means-for creating-a pressuregdiflerential betweengthe said chambers, of means for automatically pie-energizing the pump driving means when the said pressure differential drops below a predetermined amount.

2. In combination with a centrifugal pump having a main pumping chamber, an impeller in said main chamber, an auxiliary chamber communicating with said main chamber, an auxiliary impeller in said auxiliary chamber and means for driving said impellers, of means for creating a pressure differential between said chambers and means for automatically de-energizing the pump drivin means when said pressure difi'erential drops elow a predetermined amount.

3. The combination of a centrifugal pump having a main pumping chamber, an impeller in said main chamber, an auxiliary chamber communicating with said main chamber, means forsupplying liquid free from injurious material to said auxiliary chamber, an

' auxiliary impeller in said auxiliary chamber,

said impellers and chambers being adapted to create a pressure differential between said chambers, means for driving said impellers, and means for automatically de-ener 'zing the pump drivin means when the sai pressure difi'erential rops below a predetermined amount.

having a plurality of communicating chambers, impellers in said chambers, means for driving the pump, separate fluid inlets leading to said chambers means for creating a pressure differential between said chambers and means for stopping said pump driving means when said pressure differential reaches a predetermined value and starting said pump driving means when the pressure differential reaches another predetermined value.

5. The combination of a centrifugal pump having a main pumping chamber and an auxiliary chamber communicating with said main chamber,impeller means in said chambers-for creatin a pressure differential between said cham ers, means for driving said pump, means for controlling the operation of said driving means and means responsive to changes in said pressure differential for actuating said controlling means.

In testimony whereof I hereunto afiix my signature this 27th day of Ma 1929.

FRANK ALLEN.

4. Thecombination of a centrifugal pump 

